1. Field of the Invention
The present invention pertains generally to the cleaning of vessels, and more particularly to an improved siphon capable of dislodging residue and pumping the resulting liquid and residue mixture from the vessel. The teachings of the present invention are illustrated in a most specific and advantageous manifestation as a tool for cleaning recreational vehicle water heaters.
2. Description of the Related Art
Whenever a group of people gather and discuss the inventions that have had the most profound effect on the world, at least one old-timer that remembers the early days will suggest that indoor plumbing should be considered as one of the most profound. What we take for granted today was extremely important to the development of our modern society, bringing not only great convenience and time-savings, but also very greatly advancing the health and welfare of the population. With plumbing and the sanitation that was derived directly therefrom, densely populated cities have been able to develop and thrive, while remaining free of what used to be very common ailments and diseases. A large number of more specific improvements have continued to occur over time, further advancing the utility of plumbing. These advances have further improved health, welfare, convenience, aesthetic appearance, and other beneficial areas.
One such noteworthy improvement is the modern capability to transport a fully self-contained plumbing system, wherever modern man travels. Not only is fresh drinking water transported and provided through a safe and convenient faucet and pressurized line, but in many additional instances, such as within a recreational vehicle (RV) or the like, there will also be a waste storage system and a water heater. The water heater provides a limited amount of hot water on demand, often used by a person for various cleansing tasks, cooking and consumption.
Another noteworthy improvement in the plumbing industry has been the use of copper as the material for fresh-water pipes. Copper is advantageously used for the freshwater lines since it provides important biocidal activity, inhibiting the growth of bacteria, yeast, fungi and algae. Even when ion exchange occurs between impurities in the water and the copper, the copper will remain bio-active. The bio-activity will continue, so long as a sludge or film has not isolated copper ions from the water. Furthermore, even when leached into the water in the low quantities as occurs in such a plumbing system, copper is non-toxic. Consequently, water may be retained within copper pipes for reasonable durations within a plumbing system without becoming odorous or toxic.
Unfortunately, many of the portable systems described herein above, including those with water heaters, sit idle for many months at a time. A recreational vehicle may be used for only a few weeks or months out of a year, the rest of the time remaining parked. Even if the water within the pipes were to remain suitable, a water heater presents a very different environment.
The unique environment within a water heater, when compared to ordinary pipes and pumps, comes with elevated temperatures and the containment of a large relatively stagnant volume of water. Within the containment of the water heater vessel, it is quite common for sludge and particulate to precipitate. As the water heater ages, rust, scale and other impurities continue to deposit and accumulate on the walls and adjacent to the bottom. The minerals, rust flakes, and other contaminants can literally fill the bottom of the tank.
The deposits form both a thermal barrier to the introduction of heat, either through the vessel walls in the case of a gas heater, or from the element into the liquid in the case of an electric heater. The precipitate also forms a mass which is not biocidal and which can therefore sustain the growth of offensive and potentially toxic microbes. Any standing water which sits for durations measured in months within a water heater vessel will consequently tend to foul and produce an associated unpleasant odor. In some instances, it is also possible for the impurities to corrosively interact with the tank, and thereby accelerate local corrosion. Furthermore, as is known, as these sediments accumulate the water heat will lose operational efficiency and will also likely fail earlier.
The extended periods and the accumulation of sludge and other materials common to a water heater will lead to fouling of the water and generation of offensive odor, the contents which is not readily flushed from the plumbing system. Copper, which exhibits biocidal activity, is somewhat more expensive than other alternative materials, and not widely used in water heaters. Nor is this biocidal activity sufficient to overcome the sludge and precipitates. Other materials have been used within plumbing systems through time, and iron plumbing is also relatively commonplace, as are various iron alloys and coated or plated steel. Plated steel offers an excellent compromise between cost and corrosion resistance, and so is commonly used. None of the ferrous materials exhibit substantial biocidal activity. Polymers such as polyvinyl-chloride and others have been used within plumbing systems, but these polymers do not provide any biocidal activity, and instead are now known to be prone to the formation of harmful biofilms. Furthermore, the polymers also do not readily conduct thermal energy, and so are undesirable for use in combustion-type water heaters, such as gas water heaters. In addition, no reasonably-priced polymers exist which may be safely used as the containment vessel within a water heater. Consequently, most plumbing systems prefer to use polymer plumbing only for waste-conveyance. Finally, some of the most expensive systems rely on stainless-steel alloys. These are far less common, owing to the cost, and like the steel counterparts offer far less biocidal activity than copper. In the end, it is just not plausible or practical through materials science to provide a water heater vessel material which is reasonably priced, safe for potable water supplies, and also sufficiently biocidal to preserve the high-impurity content water found within a heater vessel for extended periods.
While copper pipes are more likely to preserve the water, and are readily easily flushed simply by running fresh water through for a brief time period, the same is not true for the tanks. When preparing such a tank for the next use, a person is forced to run a great deal of water to remove the residue from the tank. Consequently, a great deal of time and effort is spent not only with desirable draining, but in the flushing of the tank and associated preparation immediately before use. This time is in distinct contradiction to the primary benefit of a recreational vehicle, which is the “ready-for-travel” nature of such a fully-equipped vehicle.
To protect the water systems from damage due to freezing, or simply to prepare the plumbing system for extended storage, water lines and the water heater are commonly drained. This may at first blush appear to provide the solution to longer term storage. However, while water lines often may be fully drained, many water heaters will still retain a small amount of water adjacent to the bottom of the vessel. This remnant water adjacent the bottom of the tank is invariably the most highly contaminated water within the tank, where the most material has been deposited. With the prior art techniques for draining, these water heaters will foul even when drained. As may be apparent, no viable and effective solution exists to leaving an RV water heater idle for extended periods, even though this is typical for most recreational vehicles so equipped.
While portable plumbing systems such as found in recreational vehicles have been primarily discussed, many of the same issues arise with plumbing systems found in geographically static structures such as buildings and houses. In particular, it is quite common to accumulate a great deal of scale, precipitate and other deposits within a building or household water heater. Like the RV counterpart, many water heaters do not provide a ready way to fully and completely open and clean the interior of the water vessel. Instead, most commercially available water heaters, RV or otherwise, are fitted with some type of drain valve to which a hose may be coupled. The opening into the water heater is frequently quite small and restricted, preventing most persons from accessing the interior of the vessel. These openings are also most commonly slightly above the lowest point within the vessel. Once again then, cleaning is greatly inhibited, with the owner relying primarily upon flushes of smaller suspended particulate. The larger particulate and sludge remain within the tank. In the case of most home water heaters however, there are rarely times where water will remain stagnant for extended intervals. Consequently, it is much less common for there to be any issue with an accumulation of biofilms or microorganisms, or the development of offensive odor.
Potable water systems are not the only plumbing systems which could benefit from a more thorough cleaning than was heretofore possible. Consequently, a review of other systems is also appropriate, though other than the references made in the present disclosure these systems may share little or nothing in common, nor provide any teachings to those skilled in the art of water heaters. One feature which is important with respect to the present invention and the teachings found herein is the presence of a water vessel within which undesirable contaminants may be found, and for which there does not exist an optimum way to thoroughly clean and flush the system. Such systems are found not only in water heaters but in some cooling systems, aquariums, swimming pools and swimming pool filters, and many other systems.
To clean such systems, it is known to introduce fresh water into the system while simultaneously siphoning off water containing the undesirable contaminants, impurities or particulates. One example of known siphon-type cleaning systems is found in U.S. Pat. No. 6,517,320 by Reynolds, entitled “Hose siphon,” the contents and teachings which are incorporated herein by reference. The Reynolds invention is designed for cleaning a swimming pool sand filter, and illustrates a fresh water faucet inlet split between a cleaning line and a siphon priming line, the cleaning line and a siphon drain line entering into the swimming pool sand filter, and a junction between the siphon priming line and the drain line. The turbulence created within the filter is intended to entrain the sand or other debris, and permit the debris to then be carried through the siphon line to some discharge point. However, because the Reynolds invention uses separate lines for cleaning and siphoning, the size of these lines is undesirably limited to an undesirably small percentage of the cross-sectional area available for a given opening. Furthermore, the ability to manipulate these lines is quite limited, other than controlling the depth of insertion into the filter. For a sand filter, the depth may be the only factor of interest. However, in the case of other vessels where sediment, films and other deposits may accumulate at any level or elevation within the vessel, simply creating turbulence at the bottom will be inadequate.
The separation of control valves from adjacent the water vessel opening is also inconvenient in the Reynolds invention, requiring the operator somehow monitor the operation at a distance. Once again, this may be irrelevant in the case of a sand filter, where an overflow of the filter might be relatively inconsequential. However, in the case of a water heater with only limited space between drain outlet and the bottom of the heater, and the likelihood that leakage from the water heater could damage adjacent furnishings or finished surfaces such as floors, floor coverings, or other furniture or appliances, it would be very desirable to be able to simultaneously control both the operation of the siphon and also the fresh water inlet. The operator will also have to closely monitor the siphon hose, to ensure that within the turbulent water the siphon inlet does not wander into a surface within the vessel and then remain held there by the siphon vacuum.
Finally, the Reynolds patent illustrates a siphon-priming valve which is displaced from the convergence with the siphon line, and which evidently is only suitable for priming. This is due to the fact that water exiting from 17a will be flow-limited by the valve, and then will accumulate within line 9, consequently losing nearly all kinetic energy. In other words, the Reynolds siphon is only able to siphon liquid to a point lower than the level of water within the sand filter. Once again, in the case of a swimming pool sand filter, this may be generally adequate. Nevertheless, this undesirably limits the available application to above-ground sand filters or to sand filters with a readily accessible nearby drain into which the siphon hose may be inserted. In contrast to the sand filter, a water heater commonly is located such that the drain opening is only a few inches above the ground level. In such cases, it may be difficult or impossible to initiate and sustain a suitable siphon into a suitable receptacle or available drain.
A similar though somewhat more basic combination of a spray line and a siphon line entering into a swimming pool sand filter is illustrated in U.S. Pat. No. 4,943,211 by Boegh, entitled “Sand filter cleaning system,” the contents and teachings which are additionally incorporated herein by reference. Patents that illustrate other background siphon devices, the contents and teachings which are incorporated herein by reference, include U.S. Pat. No. 3,645,452 by Stoeckel et al, entitled “Tank Cleaner;” U.S. Pat. No. 5,133,484 by Globert et al, entitled “Suction tube device;” French patent 2,630,011 by Raigneau, entitled “Apparatus for introducing a clean washing liquid into a container and removing the used liquid by siphoning, in particular for washing the stomach of a patient;” and German patent 4,330,430 by Hini et al, entitled “Installation for the separation and extraction of liquid.” Other patents, the contents and teachings which are incorporated herein by reference, illustrate the use of various tools in combination with siphons: U.S. Pat. No. 4,722,670 by Zweifel, entitled “Aquarium pump and cleaning system;” and U.S. Pat. No. 5,152,026 by Scarpine, entitled “Cooling tower cleaning device.” Finally, a number of artisans in the heretofore unrelated field of fluid pumps have developed various jet pump technologies, the contents and teachings which are incorporated herein by reference, including: U.S. Pat. No. 5,167,046 by Benson, entitled “Induction vacuum;” U.S. Pat. No. 5,322,222 by Lott, entitled “Spiral jet fluid mixer;” U.S. Pat. No. 5,556,259 by Hlavenka, entitled “Vortex generating fluid injector assembly;” U.S. Pat. No. 6,261,067 by Popov, entitled “Liquid-gas jet apparatus having a predetermined ratio for a cross-section of an active liquid nozzle and a mixing chamber;” U.S. Pat. No. 6,269,800 by Fischerkeller et al, entitled “Device for feeding fuel;” U.S. Pat. No. 6,471,489 by Hua, entitled “Supersonic 4-way self-compensating fluid entrainment device;” U.S. Pat. No. 6,537,036 by Broerman et al, entitled “Flow amplifying pump apparatus;” U.S. Pat. No. 6,547,532 by Gonzalez et al, entitled “Annular suction valve;” U.S. Pat. No. 6,575,705 by Akiyama et al, entitled “Jet pump throat pipe having a bent discharge end;” U.S. Pat. No. 6,783,334 by Sanderson et al, entitled “Hydraulic pump reservoir having deaeration diffuser;” and U.S. Pat. No. 6,904,769 by Ogata et al, entitled “Ejector-type depressurizer for vapor compression refrigeration system.”